Hyaluronic acid derivatives have been described, U.S. Pat. Nos. 6,699,471; 6,723,709; 5,502,081; 5,616,568; 5,502,081; 6,537,979; 6,294,202; 6,703,041; 6,610,669; 6,749,865; and 6,521,223. Many of those derivatives are used primarily to reduce adhesions at sites of surgical intervention.
A chemically modified hyaluronic acid and carboxymethylcellulose combination is commercially available in film form (Seprafilm™, Genzyme), U.S. Pat. Nos. 4,937,270 and 5,017,229.
Generally, the hyaluronic acid derivatives have physical and chemical properties that differ from the native compound, the derivatives have higher residence time, generally owing to increased viscosity, and can be manufactured into devices without losing many of the biocompatible properties of the native compound. Such modifications are required because hyaluronic acid is characterized by a very rapid absorption. Nevertheless, hyaluronic acid is attractive because the molecule is not covalently bound to protein.
Kulkarni (U.S. Pat. No. 6,822,064) teaches polymerized macromers containing, for example, N-acetylglucosamine (NAG). The molecules of interest comprise a backbone molecule to which NAG, among many other sugars, is covalently bound. The macromers bind to and inactivate lysozyme. The macromers are stable and resistant to degradation.